Slewing gear for drag-line excavators, grab excavators, revolving shovels, and the like



GRAB ExCAvAToRs SeptA 8. 1925. I

H BEDGooD SLEWING GEAR FOR DRAG LINE EXCAVATORS,

REVOLVING SHOVELS AND THE LIKE Filed July 10. 1924 2 sheets-sheet 14GRAB ExcAvAtroR's Sept. 8, 1925.

2 Sheets-Sheet 2 Il im Patented Sept. 8, 1925.

UNITED STATES g VI-IU'BIRT OSWALD BEDGOOD, 0F GLASGOW,

SCOTLAND, ASSIGNOR TO LOBNITZ & CO'M- PANY LIMITED, OF RENFREW,SCOTLAND.

SIEWING GEAR FOR DRAG-LINE EXCAVATORS, GRAB EXCAVATORS, REVOLVINGSHOVELS, AND THE LIKE.

Application led July 10,

To all whom t may concern.:

Be it known that I, HUBERT OswALD BED- ooon, of Beechmount, 14 DalkeithAvenue, Dumbreck, Glasgow, Scotland, a subject of the King of GreatBritain, have invented certain new and useful Improvements in SlewingGears for Drag-Line Excavators, Grab Excavators, Revolving Shovels,y,and the like, of which the following is a specification.

This invention relates to drag line eX- cavators, grab excavators,revolving shovels and the like and has for its object to provide animproved slewing gear for the revolving platform or turntable carryingthe jib of the machine.

At present it is usual to operate the revolving platform or turntable bymeans of a circular rack and pinion gear, the rack being fixed and thepinion being on the turntable and meshing with the rack and runninground the same to rotate the turntable and slew the jib.

According to this invention the slewing is effected by meansE of awinding winch and drum mounted on the revolving platform or turntable ofthe machine the winding drum acting on one or more ropes which passround and frictionally grip a stationary part of the machine.

A convenient embodiment of the invention will now be described, by wayof eX- ample, with reference tothe annexed drawings which show only suchparts of a drag line excavator as are necessary to enable the inventionto be understood.

Fig. 1 is a side elevation showing the slewing gear and slewing engineof the eX- cavator.

Fig 2 is a plan view thereof. p

Fig. 3 is an end elevation of the gear and engine looking from theforward or jib end of the excavator.

Fig. 4 is a detail view showing the rope tightening gear and guidingsheaves with part in vertical sect-ion along the centre line of Fig. 2.

The drag line A and its fairlead B and part of the jibi C are shownmerely to illustrate the relative positions of the parts.

The numeral 1 denotes the underframe mounted, as usual, for linearmotion on rails. On the upper surface of this frame 1- is a circularroller race 2, concentric with which 1924. Serial No. 725,251.

butv of greater diameter is a circular frame 4 comprising twolsuperimposed channel bars 4a and '4b secured to the upper surface of theunder frame 1. Two double sheaves 5 and 5a of equal. vdiameter aremounted in recesses inthe revolving platform 3 in a transverse verticalplane tangential to the aforesaid frame 4 at its foremost part. Thespindle of the sheave 5 is placed slightly higher than that of sheave 5,the lowest points of the grooves of the two sheaves being in horizontalplanes through the centre lines of 'the upper and lower channels, 42Land 4b respectively.V v

At the forward end of the frame 4 two openings 6a and 6b are formed, theformer in the upper channel and the latter in the lower channel. Justinside the openings two coi-axial sheaves 7 and 7a are mounted on theframe 4 with their common axis sub-- stantially vertical.

A two-cylinder horizontal steam engine 8 is secured athwart therevolving platform 3. Through a coupling 9 and spur gear 10 the enginedrives a winding drum 11 whose axis lies in the plane of the centreline'ofv the'revolving platform 3, its central transverse plane being inthe plane of the sheaves 5 and 5a, hereinbefore mentioned.

Two jockey pulleys 12 and 12*1L are anchored to the under frame 1 withinthe frame 4, in the positions shown in Fig. 2 by screw coupling rods 13,13a.

The wire rope X, by which the slewing is effected, is double and isendless. .Starting from the jockey pulley 12", Where the two plies ofrope are separated and the said pulley inserted between them, the pliescome together and are led round lone side of the upper sheave 7, thenround the upper channel ring 4a in a counter-clockwise direction to thefore end of the frame 4 until they reach the opening 6a Vwhere thedouble rope passes outwards and leaves the ring in a tangentialdirection passing round the sheave 5 and thence round the drum 11.

From the drum 11 the rope passes on (to the left in Fig. 3), round thesheave 5a, whence it meets the lower ring 4b, round which it describes acomplete` circle in a counter-clockwise direction back to the lowersheave 7 where it passes through the opening 6b to the inside of theframe 4. Here the two plies are again separated and the second ockeypulley l2 inserted therebetween. By tightening up the screw couplings13, 13a securing the pulleys 12 and 12a any desired degree of tensionmay be placed on the wire rope.

When slewing the rope is wound in on one side of the drum and paid outon the other, producing rotary motion of the platform.

It will be apparent from the foregoing description that7 according tothis invention, a very simple and effective method of slewing a dragline excavator jib is provided, whereby toothed gearing and the usualcircular rack are dispensed with, the ifrictional grip of four plies ofWire rope being' substituted therefor.

ril'he invention also can be applied to grab excavators7 revolvingshovels and the like.

Having now fully described my invention what l claim and desire tosecure by Letters Patent is An apparatus of the character describedincluding in combination, a stationary circular frame embodyingsuperposed channel like members, pulleys within the frame, anchors forthe said pulleys, each of' the said anchors including screw couplingrods, a winding drum, and an endless rope or cable, said rope or cablebeing doubled and passing around the said winding drum, the rope orcable on one side of the drum passing around the upper channel member ofthe said frame to one of the said pulleys, the rope or cable on theother side of the drum passing around the lower channel member of thesaid frame to the other of the said pulleys.

ln testimony whereof l affix my signature.

HUBERT OSfl/VALD BEDGOOD.

